The 44-month project will begin in November with utilities relocation, which will set the stage for excavation under Howard Street, which will require 1,500 truck trips and the temporary closure of Howard Street between Third and Fourth streets for 15 to 20 days. The next phase includes the demolition and replacement of the esplanade building, which will require a combined 4,800 truck trips.

City Architect Edgar Lopez, who is overseeing the design with architect SOM, said the project will be particularly challenging because Moscone is not going to close during construction.

"This is being mapped out with military precision - we need to do construction in a way that allows Moscone to conduct its day-to-day business," Lopez said. "It's a surgical approach that involves moving in, getting work done, disappearing and quickly moving back in again. It's a lot of hurry-up-and-stop work."

The Public Works Department got some sense of the project's logistical challenges four years ago when it completed a $56 million renovation of the facility. It was like musical trucks - as 18-wheelers packed up major exhibitions, general contractors circled the block waiting to move in. "One moves out, and the other moves in," Lopez said.

Thursday's vote will be the project's last major hurdle, but the Board of Supervisors still must sign off on it.

The biggest early critic of the plan, John Elberling of Todco Group, the South of Market affordable housing organization, said he is now mostly satisfied with the design. Changes include strengthening the facade along Howard Street and scaling back the part of the building that faces the children's playground on the west side of the site.

The city has also agreed to renovate the children's play areas simultaneously with the Moscone expansion. The plan also calls for sidewalks to be widened in places and red traffic arrows to be installed at Howard and Fourth streets and Folsom and Fourth streets, which will cut down on the number of cars making illegal right turns there, said Elberling.

"When you put it all together, there will be all these pedestrian improvements we have been trying to get for decades," he said. "We are pretty much satisfied - we just have to dot some i's and cross some t's."

Lopez said the changes forced by the neighborhood have been good ones.

"We don't feel it's a compromise. It works for them and for us and makes the project better. We are extremely happy that we are moving it forward - we are ready to get going with the job," he said.

The proposed project is focused primarily on Moscone North and South, with no changes at Moscone West. Overall Moscone will grow from 1.2 million to 1.5 million square feet.